# Backup Disk vs PDF Lock & Unlock

The clearest difference is price: Backup Disk at Free against PDF Lock & Unlock's $0.99. PDF Lock & Unlock's advantage is in-app purchases (none vs 3). On ads, device support and iOS requirement there is nothing between them.

Backup Disk is free to download; PDF Lock & Unlock costs $0.99 up front. Backup Disk sells 3 in-app purchases, starting at $2.99 per month. PDF Lock & Unlock asks for nothing beyond the download.

## The numbers

| Metric | Backup Disk | PDF Lock & Unlock |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 9 months | — |
| Size | 4 MB | 25 MB |
| Requires iOS | 16.0 | **15.1** |
| Devices | iPhone, iPad, Mac | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Muharrem Ozkan](https://appshunter.io/developer/443806426) | [StudyBridge LLC](https://appshunter.io/developer/1830101876) |

## What reviewers say

### Backup Disk

[App page](https://appshunter.io/ios/app/backup-disk/id6444174393)

**Features:** Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Backup Disk PRO Monthly | $2.99 | per month |
| Backup Disk PRO Annual | $9.99 | per year |
| Backup Disk PRO Lifetime | $19.99 | one-time |


### PDF Lock & Unlock

[App page](https://appshunter.io/ios/app/pdf-lock-and-unlock/id6756542477)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Backup Disk free?

Backup Disk is free to download, with in-app purchases available.

### Is PDF Lock & Unlock free?

PDF Lock & Unlock costs $0.99, with no in-app purchases.

### Do Backup Disk or PDF Lock & Unlock have ads?

Neither Backup Disk nor PDF Lock & Unlock shows ads.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*